Amplifier with a MOS output stage

1. Field of the Invention An amplifier including first, second, and third series-connected stages, the third stage including a MOS output transistor having its source or drain forming an output terminal of the amplifier, including means for detecting the transition from a first operating state of the output transistor in which the drain current varies little with the voltage between the drain and the source to a second state in which the drain current varies substantially proportionally to the voltage between the drain and the source; and means for, upon detection of such a transition, having the voltage gain of the amplifier and/or the product between the bandwidth of the amplifier and the voltage gain of the amplifier at the upper limit frequency of the bandwidth drop.